Fluid-pressure regulator.



. I PATENTED FEB. 5,1907. W. J. RICHARDS? FLUID PRESSURE REGULATOR.

APPLICATION FILED AIR-7.1904.

Uniirnn srarns PATH NT @FFEUE.

FLUED F RESSUHE Specification of Letters Patent.

Petentec'i Feb. 5, 1907.

Applicetion filed its] 7, 1904. Serial mi 202,012.

T all whom it may concern.- Be it known that I, WALrEn J. RIoHARDs,

. residing in Milwaukee, in the county of Milwaukee and State of Wisconsin, have invented new and useful Improvements in Fluid- Pressure Regulators, of which the following is a description, reference'being had to the ac company'ing drawings, which are a part of this specification. I

This invention relates to certain new and useful improvements in fluid-pressure regulators, and has for its object to provide oer tain novel means for maintaining a given range 0f-fluid-pressure in fluid-pressure systerns by automatically starting and stopping the motorcompressor at predetermined minimumaryd maximum pressures in the fluidweak touchin pressure system.

A further object of this invention is to accomplish the above result by means substantially as the following: A solenoid-operated main sgvitch for the motor-circuit whose solenoid s energized and deenergized indirectly by mc ans of a primary switch sensitive to'the pressure of the fluid-pressure system, said primary switch cooperating with motorstarting and'supplemental switches, the motor-starting switch for energizing the solenoid of the main switch serving to short-circuit the primary switch and its own actuating-solenoid and the supplemental switch for de energizing. the solenoid of the main switch serving to short'circuit said solenoid of the main switch/ Whereas heretofore devices for somewhat similar purposes have'been provided with a primary switch, which, though making only a g contact, is relied upon to carry a heavy current for starting the ureter and which is only short circuited on the completion of the operation of the main switch, it is one of the principal objects of this invention to relieve the primary switch of the'ne oessity for carrying more amount of current, insufficient for the operaion of the motor and even ror the operation of the main switch by providing in ctor-st arting and supplemental switches which alone are actuated by the contacts made by the primary switch and which have the function of energizing and denergizing the solenoid of the main switch.

Another object of this invention is to produos a motor-starting switch for energizing than a very smallv the solenoid of for holding it closed until the main switch has completed its operation.

With the above and other objects in view the invention consists in the devices and parts and their equivalents to be hereinafter set forth.

in the accompanying drawing the figure represents a diagram of a system for automatic control of motor-compressors exemplifying this invention.

In this drawing, 1. represents a line-wire, which is here shown to be of a grounded'circuit, but which may equally Well be for a metallic circuit, and 2 is a wire connecting it with the solenoid 3 of a main or motor switch 4,, the solenoid 3 being connected to, a contact 5. which is engaged by the switche when its solenoid is energized. Another contact 6 is engaged at the same time by the switch 4 and is connected with said contact 5 by-means of the switch 4 when the switch is closed and is connected by means of a wire 7 with a motor-compressor 8, which has its other terminal connected by a wire 9 with the ground.

A wire 10 connects the contact 5 with a high-resistance solenoid 1 1 of a niot orsstarting switch 12, and awire 13 connects the-solen oid 11 with the minimum contact-point Moi a primary switch 15. This primary switch has a contact-arm 16 capable of movement toward and away from the contact 14 the result of varying pressure in a Bourdon tube 17 connected with the fluid-pressure system, and said arm 16 is connected by a wire '3 with a wire 19, which extends from a contact 0 20 of the motOrstarting switch 13 to the wire 7, where it connects with the motor 8.

More in detail, the primary switch 1 5 com-- prises the Bourdon who 17, e ith its movable end connected by a link 21. with an arm of a pivoted segmental gear 22, which meslcs with a pinion 23 carried by the contact-arm 16,,so that as tlie Bourdon tube expands an d contracts, due to the variations in pressure in the fluid-pressure system, tlze contact-arm 16 l is caused to inove hetn een the minimum c u1- i tact 14 and a maximum contact 24, wlich contacts are capable of adjustment in an areshaped slot 25 to regulate the connections of tie contact-arm 16 nith the contacts H and l 24 so as to take place at predetermined minimum and maximum pressures in the fluid-- l pressure system.

the main switch having means A contact 26 is adapted to be connected with the contact 20 when the motor-starting switch 12 is closed and has connected to it a low-resistance series sw itch-retaining solenoidlY, a'l'l'ecting the core of solenoid 1.1 and also connected to the ire 10. it is not necessary for the proper operation of the retaining-coil that it should be connected. as above described, as the solenoid 1.1 may have any other connection so long as the contact made by the arm 16 with the contact 14 completes a circuit therethrough to opera to the motorstarting switch 12.

A wire 28 connects the maximum contact 24 of the primary switch 15 with a solenoid 29 of a supplemental switch 30, which solenoid is also connected by a w ire 31 to the ground, and a contact 32, connected by a wire to wire 10, is adapted to be connected by the supplemental switch when in its closed position to a contact 34, which is connected by a wire to the line-wire 1.

'The operation of the system is as follows: Nhen the fluid-pressure in the fluid-pressure system reaches the minimum, the contactarm 16 of the primary switch engages with the minimum contact 1 1- and completes a primary circuit from the line-w ire 1 by way "Or wire 2 and solenoid 3, through wire 10,

solenoid 11., and wire 13 to contact 14, and by the contact-arm 16 inv engagement therewith, wires 1.8 and 19, through the motor 8 and wire 1) to the ground. The current through thisprirnary circuit is comparatively small by reason of the fact that said circui includes the high resista cc of solenoid 11 of the motor-starting switch .12 and is in suiilicient for the purpose of actuating the main switch though it capable ol closin the motor-starting switch 12. The closing: oi the motor-starting switch 12 has the ell'cct oi short-circuiting the primaryswitch con nection above mentioned to prevent its arcingand also short-circuiting the solenoid 11 of such motor-starting switch, but establishes a motor-starting circuit through l series switch-retaining coil 27, which will hold the motor-starting switch 12 in engagement with. the contacts 26 and 2(), noti .i1.i; standing' the short-circuitin oi solenoid 11, until the main switch completes its chising', when the series coil 27 is slmrt-circuitcd by the main switch. Another function accom plished by the closing of the motor-starting, switch .12 is by the sl)ort-circuiting of the resistance oi the solenoid ,11 and the connection of the primary switch to pass a greater amount of current through the rnain switch solenoid 3 and cause the closing of the main switch 4, which. the current of the initial circuit was incapable of (ionic. W hen the main switch. t is closed, the solenoid 27 is shortv circuited, allowing the motor-starting switch to open, and the motor-circuit is established from line-wire 1 through wire 2 and solenoid l 1 l 1 l l l 3 of the main switch, across the main switch i from contact 5 to contact 6, through wire 7 and motor 5% and by wire 9 to the ground. The motor-com n'cssor 8 is started in its operation on the completion of the motorstarting circuit by means oi the motorstart in so itch and continues in its operation after the closing of the main sw itch, increasing the fluid-pressure in the fluid-pressure system until the main switch is opened by the primary switch indicating the maximum pressure in the fluid-pressure system by means to be now described. VIlien the pressure in the fluid-pressure system. reaches the anaximum for which the primary switch is set, the contact-arm 16 engages with the maximum contact 24 and completes a circuit through the solenoid 29 ol' the supplemental switch 30 by current passing from wire 7 through wire 11) and 18 to the contact-arm 16 and the contact 2 1 engaged thereby by way of wire28 to the solenoid 29 and from there by wire 31 to the ground. This has the eil'ect of closing the supplemental s\\ itch 230 to produce the shortcircuiting oi the main-switch solenoid 3 by connecting the contact 5 thercol with the lineire 1 by way of wires 10 and 33 across the supplemental switch 30 in engagement with inc contacts 32 and and by wire The solenoid 3 of the main switch 41- being shortcircuited, said switch opens and breaks all circuits, so that the system restored to its original condition, the motor-compressor 8 coming to rest until the pressure in the lluidpressure system again reaches the minimum, when the operation above described is repeated.

ii. prime object of the motor-starting switch. to enable the full low of current to pass through said motor-starting switch between the time of its closing and. the time 01 the operation of the main switch, so that il for any reason the main switch is not closed immediately the motor-compressor will be started by the motor-starting switch and kept in tmeration until the main switch closes. This being true, should the primary itch make its 1ninimum-pressure' contact t a time when the current upon the motor is insulhcient to close the main switch the motor-starting switch will nevertheless close a circuit through the motor to start the motor in operation and continue this function until the current upon the motor rises sulli ciently to operate the main switch.

Nith the existing apparatus previously referred to in this specification, in which the primary switch is relied upon to eli'ect the o ')eration of the main switch Without the cooperation therewith of a motor-starting switch, the operation of the primary switch, due to the riiinimuni pressure in the fluid.- pressure system at a time when the current upon the motor is insu'llicient to operate the main switch, Wlll' cause the full! flow ofCurrent to be carried by the frail primary switch luce arcing at such switch because switch leaving the minimum,

lion obviously overcome by construction. employing the moswitch.

ch the motor-starting switch draw an are on opening because of iortcircuited by the main switch and when opening because of the current arc berctln'ough being broken by the -main -ch 31 as adapted to short-cirsolenoid of th e main switch to open uin switch, it is obvious that this suppleme switch may be relied upon to acopeuing of the main switch in eve do notlimit myself .51

, l hi) i ition 0 this system to any parti culai ions of compression means operated by the :n or to a compression means at all, for it is aiso obvious that this system is applicable to other purposes than that for whichit i. been described. and may be relied upon ior tri-cv c1 'utoinatically supplying elecmatic control for purpose where autois desired from the influence of airy eqziiivalent of the primary switch, which capable or making contacts as theresult oi changi conditions.

:nniing the recital in the claims contrary to the broad interpretation of claims to cover the application. the'invention for any purpose to which it is applicable it is to be understood that these claims are not to be limited to any particular apoli it i of the invention. p Th'ou 'h the circuit established by the pri- D o a I mary switch at the nninmum contact 111- clud es the motor and the Inamet of the mam switch, the current passing through such circurt is so wean as to be entirely incapable of producing the operation of the motor or even of th 'nain switch, and consequently when later the motor-starting switch closes a circuit through these dev ces which is capable of producing their operation this circuit is re ferred to as the motor-starting circuit and is said to be closed by the motor-starting switch, and also when. the main switchis' 4 shown and described the sup' closed to establish the normal'operating-crrcuit of the motor this circuit is referred to as the motor-circuit. s v

The motor-starting switch-contacts are practically in multiple or shunt connection with the contacts of the main switch, since the resistance of the series coil 27 of the motor-starting sWitch-ma net included in the circuit established by the closing of the for- --mer, is so slight as to be insignificant, and theflow of current through the motor caused by the closing of the motor-st rting switch is practicallythe same as the flow of current through the motor when the main switch is closed. Therefore when the contact or" the motor-startingswitch is referred to asbeingpractically in multiple or in shunt with the contact of the main switch it is to be understood that by this is intended tcexclude constructions where n the resistance in the circuit established by one contact is so much greater than the resistance in the circuit established by the other contactas to be appreciable in the operation of the motor as with motorstarting resistances.

:What I claim my invention is 1.. In asystem for controlling an electric motor, a primary switch, a mctonstarting switch having its :nagnet in the circuit controlled. by the primary switch, and a main switch having its magnet in the circuit controlled. by the motor-starting switch, the contacts oi the motor-starting switch being connected practically in shunt with the contacts of the main switch without appreciable inter-- ?ning resistance.

2.111 a systernior controlling anelectric motor, a primary switch, a motor-starting switch having its magnet in the circuit contr lled by the primaryswitch, a main switch having-its magnet in the circuit controlled by the motor-starting switch, and a means influenced by the primary switch for allectinfg the operation of the main switch, the contacts of the motor-starting switch being conmeted-practically in shunt with the contacts of the main switch withoutappreciable intervening resistance.

3. In a system for controlling an electric motor, a primary switch, a motor-starting switch having its magnet in the circuit controlled. by the primary switch, a main switch. having its magnet in the circuit controlled by the motor-starting switch, the contacts of the motor-starting switch being practically in shunt connection with the contacts of the rain switch without an appreciable intervening resistance, and a supplemental switch having its magnet connected in another circuit controlled by theprimary switch and adaptedto cause the *opening of the main switch.

4. in asystemior-controlling an electric motor, a main switch for controlling the motor-circuit, a motor-starting switch for los shunt-circuit adapted to make a connection to operate the motor-starting switch, said. motor-starting switch by its operation being adapted to operate the main switch.

5. In a system for controlling an electric motor, a main switch for controlling the motor-circuit, a motor-starting switch having itsmagnet in a shunt-circuit across the mainswitch contacts, and a primary switch in said shunt-circuit adapted to make a connection to cause the operation of the motor-starting switch, said motor-starting switch by its operation being adapted to short-circuit its own magnet and the primary-switch connection and thereby eflect the operation of the mam switch. l

6. In a system for controlling an electric motor, a main switch for controlling the mo tor-circuit, a motor-starting switch having its magnet in a shunt-circuit around the main switch, a retaining-coil for the motorstartingswitch, and a primary switch in said shunt-circuit adapted to make a connection to operate the motor-starting switch, said. motor-starting switch by its operation being adapted to short-circuit its own magnet and the primary switch but including in the shuntcircuitthe retaining-coil for the motor-starting switch.

7. In a system for'controlling an electric motor, a main switch for controlling the motor-circuit, a 1notor-starting switch having its magnet in a shunt-circuit around the main switch, a 'lowresistance retaining-coil for the motor-starting switchfand aprimary' switch in said shunt-circuit adapted to make a connection to operate the motorstarting said motor-starting switch by its operation being adapted to short-circuit is own magnet and the primary-switch connection, the low-resistance retaining-coil being included in the shunt-circuit while the motorstarting switch is. operated, said motorstarting switch adapted to be held in its op erated position by said retaining-coil until the main switch completes its operation.

8. In a system for controlling an electric motor, a main switch for controlling the motor-circuit, a motor-starting switch having its magnet in a shunt-circuit around the main switch,- a low-resistance retainingecoil for the motor-starting switch, and a primary switch in said shunt circuit adapted to make a connection to operate the motor-starting switch, saidmotor-starting switch by its operatienbeing adapted to short-circuit its own magnet and the primary-switch connection by means of the low-resistance retaining-coil and adapted to be held in its operated position by said retaining-coil until the main switch completes its operation, the operation of the main switch serving to short-circuit the retaining-coil to render the motor-starting switch inoperative and close the motor-circuit with the main-switch magnet'includ ed therein.

9. In a system for controlling an electric motor, a main switch for controlling the motor-circuit, a primary switch capable of cansing the operation of the main switch, and a supplemental switch actuated by the primary switch for rendering the mainswitch inoperative by short-circuiting its magnet, the magnet of said supplemental switch being in shunt'with the motor.

10. In a system for controlling an electric motor, a main switch for controlling the motor-circuit, a primary switch capable of cansing the operation of the main switch, and a supplemental switch actuated by the pri mary switch for short-circuiting the magnet of the main switch and thereby rci'idering the main switch inoperative.

11. In a system for contri'illing an electric motor, a main switch for controlling tor-circuit, a motor-stzitrting switch having its magnet in a shunt-circuit around the mainswitch contact, a prin'rary switch in said shunt-circuit adapted to make a connection to operate the motor-starting switch, said motor-starting switch by its operation i-tdapted to operate the main switch, and a supplemental switch operated by a different connection made by the primary switch and adapted to render the mam switch inoperative.

12. In a system for controlling an electric motor, a main switch for controlling the motor-circuit, a 'motor-starting switch having its magnet in a shunt-circuit around. the mainswitch contact, a primary switch in said shuntcircuit adapted to make a connection to operate the motor-starting switch, said motor-starting switch by its operation adapt ed to short-circuit its own magnet and the primaryswitch connection and eilect the operation of the main switch, and a supplemental switch operated by a different connection made by the primary switch and adapted to i also servmg to the moshort-circuit the main-switch magnet and thereby render the main'switch inoperative.

13L In a system for controlling an electric motor, a main switch for controlling the motor-circuit, a motor-starting switch having its magnet in a shunt-circuit around the main switch, a primary switch in said shunt-circnit adapted to make a connection to operate the motor-starting switch, said motor-starting switch by its operation adapted to short circuit its own magnet and the primary switch connection and to energize the mainswitch magnet and thereby operate the main switch, and a low-resistance retaining-coil for the motor-starting switch adapted to be included in the circuit established by the oporation of the inotonstarting switch and hold. said switch in. its opera.tedposition until the main sw .oh con'ipietes its operation.

ii. In a illikl-ptess re system, :i controller for the niotor-conipressor a n'iotor-circuit, n main switch for coi'itrolling the motor-circuit end having its'niognet contained in said 1'notoi'--circuit, a shunt-circuit around the main switch, a prin'niry switch sensitiveto the pressure o'f'the fluid-messure system adopted to close said shnnt-ciicuit,

motor-starting switch. having its operstingmagnet included. inthe shunt-circuit, a retaining-coil oi lowui'esistzince for the niotorstarting switch, inotor-stsiting; switch. adapted to be operated on the closing of the shunt-cii'cuit by, the primary switch end. when operated adopted to short-circuit its own operating-magnet end the connection mede by the primary switch and substitute in the shunt-circuit the low-resistance i'etziining-coil, the operation of the motor-startingswitch and in series with the main-switch magnet, and a primary switch in said shuntcircnit adapted to make a connection to operate the H'lOtUlHStZLTiiHQ; switch, said motorstoiting switch hy its operation being adnp t ed to operate the main switch.

16. In as system for controlling an electric motor, a main switch for controll ng the 1notone? wit, a motoi st sting switch having its magnet in a shunti edit around the main. switch and in series witn the .niaiii-switch. magnet, and a primary switch in said shunt circuit adoptedto Ina-hen connection to opcrate the motonstsrting switch, said niotorstarting switch by its operation being edcptto short-circuit its own magnet and the primary-switch connection and thereby eiicct the operation 0? the main switch.

27. In system for-controiiing an electric mot thereof comprising i adopted to short-circuit its own magnet and the primary switch and include in the shuntcircuit the retaining-con for the motor-starting switch. 18. In a system foitcon trollinp an electric motor, a main switch for ccntroiiing the mo tor-circuit, motor-starting switch having its magnet in e shunt-circuit around the main switch and in series with the main-switch magnet, it iOtJ-lGSiSlISLIiCQ retaining-coi for the mo tor-starting switch, and a primary switch in said sinmt-circuit adapted to make a con necti on to op the inotonstcrting switch, said motor-stortinc switch by its operation hcing adapted to s oiocircuit its own magnet and the primary-switch connection, the low-resistance retaining-coil being included in the shun t-circuit while the motor-starting switch is operated, said motor sterting switch ode .ited to he held in its operated position by said retaining-coil until the mein switch coin-- pletes its operation as the resultof the increased current passed through its magnet due to the short-circuiting of the resistance of the motor-starting-switch magnet.

In system for controlling an eiectric nu" *1 main switch for controliinq the motor-circui having s motonstnrting SWl'hCTl its n ngne. in it shunt-circuifi around the main switch and in series with the main-switch magnet, a low-resistance retaining-coil for the 1110l10f-SiltTtiI1g switch, and a. prime-1y switch in said shunt-circuit adapted to make a connection to operste the 1110'13OP-Shfi1ili11g switch, said motor-starting s itch by its op oration being adopted to short-circuit its own magnet and the primary-switch connection by means of the low-resistance retaining-coil and adapted to he held in its operated position by said retaining-coil until the main switch completes its operation, the operation ot the inn-1n switch serving to short-c1rcu1t the retaining-cod to render the motor-stnrting switch inoperative and also serving to close ditcuit through the motor with the main-switch magnet incinded therein.

20. In n system. for ()ODi'lOilil'lQ" an electric motor, e main switch for control in the 1110-- tor-cii'cuit, a motor-sin ng switc having its magnet in c shunt-circuit around the main switch and in series with the main-switch magnet, s pi'iinssy switch in said shunt-circuit adopted to make connection to ope'inte the .iROiKOl ShiillJill switch, said motor-startingswitch by operetion adopted to open the Khalil swztci'i, end a supplemental y diiierent connection d adopted to s11 ciectric "n the mo- .e lIlOi'OT-Sllfiitiflg switch having L a shunt-circuit around the main itch and in series with the main-switch magnet) primaryf switch in said shunt-cir- IOU cuit adapted to make a connection to operate the motor-starting switch, said motor-starting switch by its operation adapted to shortcircuit its own magnet and the primaryswitch connection and thereby etlect the operation of the main switch, and a supplemental switch operated by a ditl'crcnt connection made by the primary switch and adapted to short-cirmiit the main-switch magnet and thereby render the main switch inoperative.

22. in a system for controlling an electric motor, a main switch for controlling a motor-circuit, a motor-starting switch having its magnet in a shunt circuit around the main switch and in series with the main-switch magnet, a primary switch in said shunt-circuit adapted to make a connectitm to operate the motor-starting switch, said motorstaring switch by its operation adapted to short-circuit its own magnet and the primary-switch connection to increase the amount o1 current flowing through the mainswitch magnet and thereby operate the main switch, and a low-resistance retaining-coil for the motor-starting switch adapted to be. included in the circuit established by the operation of the motor-starting switch and hold said switch in its operated position until the main switch completes its operation.

23. In a fluid-pressure system. a controller for the motor-compressor t-hereol' comprising a motor-circuit, a main switch [or controlling the motorcir 'uit and having. its magnet contained in said motor-circuit, a slmnt-circuit around the main switch and in series with the main-switch magnet, a primary switch sensitiye to the pressure of the thud-pressure system adapted to close said shunt-circuit, a motor-starting switch having its operatingmagnetincluded in the slumt-circuit, a retaming-coil o't low resistance forthe motorstarting switch, said motor-starting snitch adapted to be operated on the closing of the shunt-circuit by the primary switch and when operated adapted to short-circuit its own operatirig-magnet and the connection made by the primary switch and substituting in the slmnt-circuit the low-resistance retaining-coil, the removal of the resistance ol" the inot n'startingswitch tiperating-magnct. being adapted to cilcct the operation ol the main switch, said main switch when operated adapted to complete a circuit through the motor and short-circuit the retaining-coil ot the im tor-starting-switch, and a supplemental switch having its operating-magnet connected in shunt with the motor-colnpressor and controlled by another connection made by the primary switch and adapted in its operation to short-circuit the main-switch nmgnct.

34.. v in a system for controlling an electric motor, a. main switch for controlling the motor-circuit, a motor-starting switch adapted to cause the operation of the main switch and l l l l l l l 1 t l l supply current to the motor for starting its operation, and a mimery switch for causing the operation of the motor-starting switch, said motor-starting switch having its contact and magnet practieallyin shunt connection with the main-switch contact and adapted when caused to be operated by the primary switch to remain in its operated position until the main switch is operated.

in a system for controlling an electric motor, primary switch, a motor-starting switch adapted to he'actuated on the operation of the primary switch, and a main switch adapted to be operated on the operation of the motor-starting switch, saidmotorstart ing switch having its magnet practically in shunt *ith its contact and with the contact of the main switch, whereby it is held in its operated position until the main switch is operated. l,

26. In a system for controlling an electric motor, a primary switch, a motor-starting switch adapted to be actuated on the operation of the primary switch, and a main switch with its pcrating-magnet in series with the motor and adapted to be actuated. on the operation oi" the nmtor-starting switch.

"27. 111 a system tor controlling an electric motor, a primary switch, a motoii-stnr'ting switch relying thereon for its tmcrz'rtion. a main switch relyii'ig on the motor-starting switch lor its operation and haying its operatinganagnet in series with the motor, and a means intluenced by the primary switch for also a'll'ccting the operation of the main switch.

in a system for controlling an electric motor, a primary switch,- a nmtor-starting switch adapted to be closed by the operation of the primary switch, ama-in switch ad aptcd to be closed by the closing oi the1notm-starting switch and having its opcrating-magnet in series with the motor, and a. supplemental switch adapted to be operated by a. ditterent operation of the primary switch to cause the opening ol' the main switch.

2%). In a system l'or controlling an electric. motor. a main switch l'or controlling the mo tor-circuit having its operating-magnct in scrics with the motor, a motiw-starting switch hating its magnet in a shunt-circuit around the main-switch contacts, and a primary switch in said shunt-circuit adapted to make a connection to cause 'the operation ol' the motor-starting switch, said motor-starting switch by its operation being adapted to ausc the operation ol' the main switch.

30. in a system l'or controlling an electric motor, a. main switch tor controlling the motzir-circuit having its operating-soienoid in series with the motor, a mot or-sta rt ing switch haying its magnet in a shuntcircuit around the main-switcn contact, and a. primary switch in said shunt(.-ircuit adapted to make a connection to operate the motor-starting switch, said motor-starting switch by its opcircuit adapted to make a connection to ener- 1 erati'on being adapted to short-clrcuit its own magnet and the primary-switch connection, and effect the operation of the main switch.

, 31. In a system for controliin an electric motor, a main switch for control ing the motor-circuit having its operating-magnet in series with the motor, a motor-starting switch having its magnet in shunt with the main switch so that the closing of the main switch short circuits said motor starting switch magnet, and a primary switch in said shuntgize the motor-starting-switoh magnet and cause it to close the motor-starting switch to send an operating-current through the motor and to also energize. the m ain-switch magnet.

In testimony whereof I affix my signature in presence of two Witnesses.

WALTER J. monnnos.

Witnesses R. S. C. CALDWELL, ANNA F. SOI-IMIDTBAUER. 

